Perpendicular magnetic write head having a structure that suppresses unintended erasure of information on a write medium at a non-writing time

ABSTRACT

A perpendicular magnetic write head includes an auxiliary magnetic pole layer disposed on a trailing or leading side of a main magnetic pole layer, the auxiliary magnetic pole layer being recessed from the main magnetic pole layer. A nonmagnetic layer is disposed in a layer same as the auxiliary magnetic pole layer and in front of the auxiliary magnetic pole layer, the nonmagnetic layer having an internal stress of a direction same as that of the main magnetic pole layer, and a write shield layer is disposed in a layer same as the auxiliary magnetic pole layer and in front of the auxiliary magnetic pole layer, the write shield layer being separated from the main magnetic pole layer with a gap layer in between. The nonmagnetic layer is arranged to fill up a space between the auxiliary magnetic pole layer and the write shield layer.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a perpendicular magnetic write headprovided with an induction type magnetic transducer element for write,method of manufacturing the same, and a magnetic write system whichcarries the perpendicular magnetic write head.

2. Description of the Related Art

In recent years, improvement is required in performance of a thin filmmagnetic head, which is mounted on magnetic write systems such as a harddisk drive, associated with improvement in the surface writing densityof a magnetic write medium such as a hard disk (hereinafter just called“write medium”).

As examples of writing system of such thin film magnetic head, thelongitudinal write system which sets a direction of signal magneticfield to an in-plane direction (longitudinal direction) of the writemedium, and the perpendicular write system which sets up a direction ofthe signal magnetic field to a direction orthogonal to the plane of thewrite medium are known. Although the longitudinal write system is widelyused nowadays, it is assumed that the perpendicular write system is morepromising than the longitudinal write system in the future inconsideration of the market trend, which is affected by improvement ofthe surface writing density of the write medium. It is because theperpendicular write system has advantages that high linear writingdensity is obtained and that an already-written write medium is hardlysubject to heat fluctuation.

The thin film magnetic head of the perpendicular write system(hereinafter just called “perpendicular magnetic write head”) isprovided with a thin film coil which generates magnetic flux and a mainmagnetic pole layer which leads the magnetic flux generated in the thinfilm coil to the write medium.

As an example of such perpendicular magnetic write head, those in whichthe main magnetic pole layer extends in a direction orthogonal to an airbearing surface are known and such a head structure is generally called“single pole head.” As for such single pole head, those in which anauxiliary magnetic pole layer for magnetic flux supply is put togetherwith the main magnetic pole layer have been developed in order toincrease intensity of the write magnetic field (perpendicular magneticfield) (reference to Unexamined Japanese Patent Publication No.H02-066710 and Japanese Patent Publication No. 2002-197615, forexample). However, such single pole head is said to have a limitation inimproving the writing density of the write medium.

As for a latest perpendicular magnetic write head, in view of the above,those provided with a write shield layer for taking in a spreadcomponent of magnetic flux emitted from the main magnetic pole layer arebecoming mainstream so that the writing density can be more improved.This kind of head structure is generally called “shield type head.” Asfor such shield type head, those in which the write shield layer isdisposed on a trailing side of the main magnetic pole layer have beendeveloped (for example, refer to Japanese Patent Publication No.2001-250204 and European patent Publication No. 0360978.

Especially about the shield type head, in order to suppress unintendederasure of information written on the write medium at the time ofwriting, those in which the auxiliary magnetic pole layer is disposed onthe trailing side of the main magnetic pole layer are also developed(for example, refer to Japanese Patent Publication No. 2006-155866).

By the way, demand for writing performance of the perpendicular magneticwrite head is still more increasing day by day. Based on suchcircumstances, it has been examined recently, as an improvement measure,to optimize a magnetic domain structure of main component elements thatare engaged in writing operation.

Specifically, a magnetic film, which is made of a magnetic layercontaining a magnetic metal and a transition metal and an intermediatelayer containing a magnetic metal and a transition metal similarly, withits composition optimized in order to obtain high frequencycharacteristics, strong uniaxial anisotropy, and high saturationmagnetic flux density, is known (for example, refer to Japanese PatentPublication No. 2000-150233). As well, a magnetic material, whichincludes nickel (Ni), steel (Fe) and molybdenum (Mo), with itscomposition and magnetostriction constant optimized in order to acquirehigh frequency characteristics and a good magnetic domain structure, isknown (for example, refer to Japanese Patent Publication No.2000-235911).

Besides, other well-known examples include: a thin film magnetic head,which is provided with an upper magnetic pole whose plus and minus ofthe magnetostriction constant are reversed between an upper area and anlower area thereof in order to acquire uniaxial anisotropy in a desireddirection (for example, refer to a Japanese Patent Publication No.H07-307009 and a Japanese Patent Publication No. 1986-192011); a thinfilm magnetic head, which is provided with a yoke containing two sets ofmagnetic layers respectively having a mutually differentmagnetostriction constant and disposed so as to be partially overlappedeach other in order to suppress generating of noises caused by stressinduced anisotropy effect (for example, refer to Japanese PatentPublication No. H07-014120); and a thin film magnetic head provided witha pole chip having a zero or negative magnetostriction constant and ahead core rear having a zero or positive magnetostriction constant inorder to suppress distortion of a read waveform (for example, refer toJapanese Patent Publication No. H02-252111).

In addition, another known example is a thin film magnetic head providedwith a magnetic domain control soft magnetic layer for making a 180degree magnetic wall in a core width direction appear in a magneticdomain structure of a yoke of a magnetic layer between a coil coverwhich covers a coil layer and the yoke in order to obtain a goodmagnetic domain structure, high frequency response characteristics, anda high transfer rate (refer to Japanese Patent Application No.2000-331310).

It is to be noted that, in the recent manufacturing field of thin filmmagnetic heads, the ALD method is used as the formation method which isextremely excellent in thickness control characteristics (for example,refer to an “ALD atomic layer deposition apparatus”, by TechscienceLtd., <URL:http://techsc.co.jp/products/mems/ALD.htm>). The ALD methodis the step of forming an oxide film, a nitride film, or a metal filmvery thinly and precisely under high temperature conditions of 150degrees C. or more, and is widely used in a manufacturing field in whichphysical characteristics such as dielectric strength voltage areseverely required. In the manufacture field of the thin film magnetichead, the ALD method is used in the formation process of a read gap (forexample, refer to the specification of U.S. Pat. No. 6,759,081).

SUMMARY OF THE INVENTION

However, in the perpendicular magnetic write head of the related art, amagnetic domain structure of main component elements such as a mainmagnetic pole layer, an auxiliary magnetic pole layer and a write shieldlayer that are engaged in writing operation, is hardly optimized evennow. For this reason, there is a problem that information written on thewrite medium may be erased without intention when magnetic flux, whichremains in the main magnetic pole layer, is leaked out at a non-writingtime. In view of the drawback of the invention, it is desirable toprovide a perpendicular magnetic write head, method of manufacturing thesame, and a magnetic write system in which unintended erasure ofinformation written on a write medium can be suppressed at a non-writingtime by optimizing the magnetic domain structure of the main componentelements that are engaged in writing operation.

A perpendicular magnetic write head according to the present inventionincludes: a main magnetic pole layer leading a magnetic flux to a writemedium, the main pole layer having an internal stress of a specifieddirection; an auxiliary magnetic pole layer disposed on a trailing sideor leading side of the main magnetic pole layer, the auxiliary magneticpole layer being recessed from the main magnetic pole layer; and anonmagnetic layer disposed in a layer same as the auxiliary magneticpole layer and in front of the auxiliary magnetic pole layer, thenonmagnetic pole layer having an internal stress of a direction same asthat of the main magnetic pole layer.

A magnetic write system of the present invention includes a write mediumand a perpendicular magnetic write head, wherein the perpendicularmagnetic write head includes: a main magnetic pole layer leadingmagnetic flux to the write medium, the main magnetic pole layer havingan internal stress of a specified direction; an auxiliary magnetic polelayer disposed on a trailing side or leading side of the main magneticpole layer, the auxiliary magnetic pole layer being recessed from themain magnetic pole layer; and a nonmagnetic layer disposed in a layersame as the auxiliary magnetic pole layer and in front of the auxiliarymagnetic pole layer, the nonmagnetic layer having an internal stress ofa direction same as that of the main magnetic pole layer.

A method of manufacturing a perpendicular magnetic write head of thepresent invention includes the steps of: forming a main magnetic polelayer which leads magnetic flux to a write medium so as to have aninternal stress of a specified direction; forming an auxiliary magneticpole layer on a trailing side or leading side of the main magnetic polelayer so as to be recessed from the main magnetic pole layer; andforming a nonmagnetic layer in a layer same as the auxiliary magneticpole layer and in front of the auxiliary magnetic pole layer so as tohave an internal stress of the same direction as that of the mainmagnetic pole layer.

In the perpendicular magnetic write head, method of manufacturing thesame, or the magnetic write system of the present invention, theauxiliary magnetic pole layer is disposed on the trailing or leadingside of the main magnetic pole layer so as to be recessed from the mainmagnetic pole layer, and when the main magnetic pole layer has aspecified internal stress, the nonmagnetic layer disposed in a layersame as the auxiliary magnetic pole layer and in front of the auxiliarymagnetic pole layer, the nonmagnetic layer having an internal stress ofthe same direction as that of the main magnetic pole layer. Therefore,the magnetic domain structures of the main magnetic pole layer and theauxiliary magnetic pole layer are kept in a good state of the initialformation without being influenced by the internal stress of thenonmagnetic layer. With this arrangement, magnetic flux which remains inthe main magnetic pole layer and the auxiliary magnetic pole layer ishardly leaked out immediately after information-writing due to themagnetoelasticity effect. Accordingly, unintended erasure of informationwritten on a write medium can be suppressed at a non-writing time, byoptimizing the magnetic domain structures of the main component elementsthat are engaged in writing operation.

Other objects, features and effects of the present invention will beexplained as necessary in the following descriptions.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A and 1B are cross-sectional views showing a sectionalconfiguration of a thin film magnetic head according to a firstembodiment of the present invention.

FIG. 2 is a plan view illustrating a configuration of the thin filmmagnetic head shown in FIGS. 1A and 1B.

FIG. 3 is a plan view illustrating a configuration of a principalportion of the thin film magnetic head shown in FIGS. 1A, 1B.

FIG. 4 is a sectional view showing a configuration of the principalportion of the thin film magnetic head shown in FIGS. 1A, 1B.

FIGS. 5A and 5B are sectional views for explaining one productionprocess in a manufacturing process of the thin film magnetic headaccording to the first embodiment of the present invention.

FIGS. 6A and 6B are sectional views for explaining a step subsequent tothat of FIGS. 5A and 5B.

FIGS. 7A and 7B are sectional views for explaining a step subsequent tothat of FIGS. 6A and 6B.

FIGS. 8A and 8B are sectional views for explaining a step subsequent tothat of FIGS. 7A and 7B.

FIG. 9 indicates a magnetic domain structure of a main magnetic polelayer in the thin film magnetic head according to the first embodimentof the present invention.

FIG. 10 shows a magnetic domain structure of a main magnetic pole layerin a thin film magnetic head according to a comparative example.

FIG. 11 shows magnetic domain structures of an auxiliary magnetic polelayer and a write shield layer in the thin film magnetic head accordingto the first embodiment of the present invention.

FIGS. 12A and 12B are cross-sectional views showing a sectionalconfiguration of a thin film magnetic head according to a secondembodiment of the present invention.

FIGS. 13A and 13B are sectional views for explaining one productionprocess in a manufacturing process of the thin film magnetic headaccording to the second embodiment of the present invention.

FIGS. 14A and 14B are sectional views for explaining a step subsequentto that of FIGS. 13A, 13B.

FIGS. 15A and 15B are sectional views for explaining a step subsequentto that of FIGS. 14A and 14B.

FIGS. 16A and 16B are sectional views for explaining a step subsequentto that of FIGS. 15A and 15B.

FIGS. 17A and 17B are sectional views for explaining a step subsequentto that of FIGS. 16A and 16B.

FIG. 18 is a perspective view showing a configuration of a magneticwrite system which carries the thin film magnetic head of the presentinvention.

FIG. 19 is a perspective view showing a configuration of a principalportion of the magnetic write system illustrated in FIG. 18.

FIG. 20 shows a write width dependency of write signal deterioration.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Embodiments of the present invention will be described in detailhereinbelow with reference to the drawings.

First Embodiment

First, a configuration of a thin film magnetic head according to a firstembodiment of the present invention will be described. FIGS. 1A, 1B toFIG. 4 show a configuration of a thin film magnetic head, and FIGS. 1A,1B show a cross-sectional configuration thereof, FIG. 2 shows a planview configuration thereof, FIG. 3 shows a plan view configuration ofits principal portion, and FIG. 4 shows a cross-sectional configurationof the principal portion respectively. In addition, FIG. 1A shows across section parallel to an air bearing surface 40, and FIG. 1B shows across section perpendicular to the air bearing surface 40, respectively.FIG. 4 also shows a write medium 50 together with the thin film magnetichead, and an upward arrow M shown in FIGS. 1A, 1B, FIG. 3, and FIG. 4respectively express a direction (medium movement direction M) in whichthe write medium 50 moves relatively to the thin film magnetic head.

In the following descriptions, dimension in the X-axis direction isdesignated as “width”, dimension in the Y-axis direction is designatedas “length”, and dimension in the Z-axis direction is designated as“thickness” respectively as shown in FIGS. 1A, 1B to FIG. 4. Besides,the side close to the air bearing surface 40 of the Y-axis direction isdesignated as “forward”, and the side opposite to that is designated as“backward” respectively. These designations are used in the same wayeven in and after FIGS. 5A, 5B that will be described later.

The thin film magnetic head of the present embodiment executes amagnetic process to the write medium 50 (a hard disk, for example) shownin FIG. 4, which is a combined magnetic write and read head that canexecute both of magnetic write processing and read processing. As shownin FIGS. 1A, 1B, for example, the thin film magnetic head is formed insuch a manner that a substrate 1, an insulating layer 2, a read headsection 100A which executes a read processing using MR(magneto-resistive) effect, a separation layer 9, a write head section100B which executes a write processing of a perpendicular write system,and an overcoat layer 24 are layered in this order. The substrate 1 ismade of ceramic materials, such as altic (Al₂O₃ and TiC), and theinsulating layer 2, the separation layer 9, and the overcoat layer 24 ismade of nonmagnetic insulation materials, such as an aluminum oxide(AlO_(x): ex. alumina (Al₂O₃)).

The read head section 100A is formed in such a manner that a lower readshield layer 3, a shield gap layer 4, and an upper read shield layer 30are stacked in this order, for example. A read element (an MR element 8)is embedded in the shield gap layer 4 in such a manner as being exposedoutside on the air bearing surface 40.

The lower read shield layer 3 and the upper read shield layer 30 extendfrom the air bearing surface 40 to backward, and are made of magneticmaterials, such as a nickel iron alloy (NiFe: hereinafter just called“permalloy (tradename)). Composition of this permalloy is nickel=80 wt %and Fe=20 wt %, for example. The upper read shield layer 30 is formed insuch a manner that two upper read shield layer portions 5 and 7 arelayered with a nonmagnetic layer 6 in between, for example. The upperread shield layer portions 5 and 7 are made of magnetic materials suchas a permalloy for example, and the nonmagnetic layer 6 is made ofnonmagnetic substances such as ruthenium (Ru) or alumina, for example.It is to be noted that the upper read shield layer 30 does notnecessarily need to have a layered structure, and may have a monolayerstructure made of a magnetic material.

The shield gap layer 4 is made of nonmagnetic insulation materials suchas alumina, for example. This MR element 8 works using GiantMagneto-Resistive effect (GMR) or tunneling magneto-resistive effect(TMR) or the like, for example.

The write head section 100B is a perpendicular magnetic write head inwhich a first thin film coil 10 buried in an insulating layers 11 to 13,a main magnetic pole layer 14 buried and surrounded by a nonmagneticlayer 15, a gap layer 16, an auxiliary magnetic pole layer 17 buried andsurrounded by a nonmagnetic layer 19, a write shield layer 18, a secondthin film coil 21 buried in insulating layers 20 and 22 and a returnyoke layer 23 are layered in this order for example, which is what iscalled a shield type head. The thin film coil 10 generates a magneticflux for controlling leakage in order to suppress leakage of the writemagnetic flux that is generated in the thin film coil 21 (that is, thewrite magnetic flux affects the read head section 100A withoutintention). The thin film coil 10, which is made of high conductivitymaterials such as copper (Cu) for example, has a spiral structure inwhich the thin film coil 10 is winding around a back gap BG as shown inFIGS. 1A, 1B, and 2. Although the number of winding (turn number) of thethin film coil 10 can be set up arbitrarily, the turn number thereof ispreferably in agreement with that of the thin film coil 21.

The insulating layer 11, which is made of nonmagnetic insulationmaterials such as photoresist and spin on glass (SOG) showing fluiditywhen heated, is disposed between and around each winding of the thinfilm coil 10 for example. The insulating layer 12 is disposed in thecircumference of the insulating layer 11, and the insulating layer 13 isdisposed so as to cover the thin film coil 10 and the insulating layers11, 12. These are made of nonmagnetic insulation materials such asalumina, for example. The thickness of the insulating layer 13 is about0.05 μm to 0.2 μm. The main magnetic pole layer 14, which leads themagnetic flux generated in the thin film coil 21 to the write medium 50,extends from the air bearing surface 40 to backward. The main magneticpole layer 14 is made of magnetic materials such as an iron cobalt-basedalloy, for example, and the thickness thereof is about 0.15 μm to 0.4μm. Examples of the above-mentioned iron cobalt-based alloy include aniron cobalt alloy (FeCo) or a cobalt iron nickel alloy (CoFeNi).

The main magnetic pole layer 14, which is an abbreviated battledoreconfiguration in plan view as a whole, includes, for example, a tipportion 14A with a fixed width W1 for specifying a width of a writingtrack, a rear end portion 14B which is magnetically connected at therear of the tip portion 14A with a width W2 bigger than the width W1 inthis order from the air bearing surface 40, as shown in FIG. 2. Thewidth of the rear end portion 14B is uniformed (W2) in the backward areawhile it becomes gradually narrower toward the tip portion 14A in theforward area, for example. The position where the width of the mainmagnetic pole layer 14 begins to spread from W1 to W2 is a flare pointFP, and distance between the air bearing surface 40 and the flare pointFP is a neck height NH.

An end face of the main magnetic pole layer 14 on the air bearingsurface 40 is of an inverted trapezoid in shape whose long arm locatedon a trailing side is an upper base and whose short arm located on aleading side is a lower base respectively, for example, as shown in FIG.3. More specifically, configuration of the end face of the main magneticpole layer 14 is defined by an upper end edge E1 (width W1) located onthe trailing side, a lower end edge E2 (width W4) located on the leadingside, and two side edges E3. The width W4 is smaller than the width W1.The upper end edge E1 is a substantial writing section (what is calledtrailing edge TE) of the main magnetic pole layer 14, and the width W1is about 0.2 μm or less. Bevel angle θ, that is, an angle between anextending direction of the lower end edge E2 and the side edges E3 canbe arbitrarily determined within a range below 90 degrees.

It is to be noted that, when the movement state of the write medium 50which goes in the medium movement direction M is regarded as one flow,the “trailing side” means a side where the flow goes to (a forward sidein the medium movement direction M), which means the upper side of thethickness direction (Z-axis direction) here. On the other hand, the sidewhere the flow comes in is called the “leading side” (the rear side ofthe medium movement direction M), which means the lower side of thethickness direction here.

Especially, the main magnetic pole layer 14 has an internal stress of aspecified direction. This internal stress is a stress that remainsinside after the formation of the main magnetic pole layer 14 to affecta magnetic domain structure thereof, which is specifically a tensilestress or compressive stress. Here, the main magnetic pole layer 14 hasa tensile stress as its internal stress, for example.

The tensile stress is a stress applied in a pulling direction on thebasis of the inside of the main magnetic pole layer 14 (that is, adirection which goes outside of the main magnetic pole layer 14). On theother hand, a stress applied in a compressing direction (that is, adirection which goes inside the main magnetic pole layer 14) on the samebasis is the compressive stress.

The nonmagnetic layer 15 is made of nonmagnetic insulation materialssuch as alumina, for example. This nonmagnetic layer 15 is made flatwith the main magnetic pole layer 14, for example, and thickness thereofis the same with that of the main magnetic pole layer 14. The gap layer16, which extends from the air bearing surface 40 up to the front end ofthe auxiliary magnetic pole layer while adjoining the main magnetic polelayer 14, is made of nonmagnetic insulation materials such as alumina,for example. As for the gap layer 16, a portion put between the mainmagnetic pole layer 14 and the write shield layer 18 is a magnetic gapfor separating both of them, with its thickness about 0.03 μm to 0.1 μm.

The auxiliary magnetic pole layer 17, which supplies magnetic flux tothe main magnetic pole layer 14, extends from a retreating positionrather than the air bearing surface 40 to the backward direction. Thisauxiliary magnetic pole layer 17 is made of magnetic materials such as apermalloy or an iron-cobalt based alloy for example, and is a rectanglein shape in plan view with a width W2, as shown in FIG. 2. In addition,the auxiliary magnetic pole layer 17 is formed thicker than the mainmagnetic pole layer 14, with a thickness of about 0.5 μm to 1 m in orderto earn an enough magnetic flux capacity (namely, what is calledmagnetic volume).

Especially, the auxiliary magnetic pole layer 17 is disposed on thetrailing side or leading side of the main magnetic pole layer 14 and ismagnetically connected with the main magnetic pole layer 14. Here, theauxiliary magnetic pole layer 17 is disposed on the trailing side of themain magnetic pole layer 14, for example. The structure where theauxiliary magnetic pole layer 17 is disposed on the trailing side iscalled top yoke structure.

The write shield layer 18 takes in spread components of the magneticflux to be led to the write medium 50 emitted from the main magneticpole layer 14 so as to (1) increase magnetic field gradient of aperpendicular magnetic field, (2) to narrow a write width, and (3) toinclude an oblique magnetic field component in the perpendicularmagnetic fields. The write shield layer 18, which is disposed in an areain front of the auxiliary magnetic pole layer 17 in a layer same asthat, and extends from the air bearing surface 40 to a front position ofthe auxiliary magnetic pole layer 17, while separated from the mainmagnetic pole layer 14 by the gap layer 16. In addition, the writeshield layer 18 is made of magnetic materials such as permalloy oriron-cobalt based alloy for example, and is a rectangle in shape in planview with a bigger width W3 than the width W2 of the auxiliary magneticpole layer 17, as shown in FIG. 2. A nonmagnetic layer 19, whichspecifies a throat height zero position TP, adjoins the back end of thewrite shield layer 18. Namely, the write shield layer 18 has a functionof substantially specifying the throat height zero position TP in thatback end.

The nonmagnetic layer 19 specifies the throat height zero position TP atthe front edge thereof, and a distance between the air bearing surface40 and the throat height zero position TP is a throat height TH. It isto be noted that FIGS. 1A, 1B, and FIG. 2 show a case where the throatheight zero position TP is in agreement with the flare point FP, forexample. The nonmagnetic layer 19 is disposed in an area in front of theauxiliary magnetic pole layer 17 in a layer same as that, and fills up aspace between the auxiliary magnetic pole layer 17 and the write shieldlayer 18. Here, the nonmagnetic layer 19 is disposed so as to fill notonly the area in front of the auxiliary magnetic pole layer 17 in alayer same as the layer, for example, but also bury the periphery of theauxiliary magnetic pole layer 17. The nonmagnetic layer 19 is made ofnonmagnetic insulation materials such as an aluminum oxide (for example,alumina) or aluminum nitride, and nonmagnetic conductive materials suchas ruthenium, for example.

Especially, the nonmagnetic layer 19 has an internal stress of adirection same as the internal stress of the main magnetic pole layer 14in order to optimize the magnetic domain structure of the main magneticpole layer 14. Here, the nonmagnetic layer 19 has a tensile stress aswith the main magnetic pole layer 14, for example. The nonmagnetic layer19 is formed by a manufacturing method, which is capable of producingthe tensile stress when the above-mentioned nonmagnetic insulationmaterials and the nonmagnetic conductive materials are used, forexample, by the ALD method.

In a case where both of the nonmagnetic layer 19 and the gap layer 16are made of alumina, the nonmagnetic layer 19, which is formed by theALD method, is composed differently from the gap layer 16 formed by amethod other than the ALD method (by sputtering for example) even thoughthey are made of the same material. Namely, since the gap layer 16 isformed by way of sputtering or the like, which uses an inert gas, itnaturally contains the inert gas therein. Examples of such inert gas areargon (Ar), krypton (Kr), or xenon (Xe). On the other hand, thenonmagnetic layer 19 does not contain any inert gas because it is formedby such method as ALD, which does not use inert gas. Incidentally,whether or not the nonmagnetic layer 19 and the gap layer 16 include anyinert gas can be specified using such component-analysis systems asscanning transmission electron microscopy (STEM), energy dispersiveX-ray spectroscopy (EDS) and so on.

Besides, the nonmagnetic layer 19 and the gap layer 16 has a differencein the amount of a specific component contained therein because of themutual differences in the above-mentioned formation method. Namely, theALD method uses water and trimethyl aluminum (TMA), while the sputteringmethod does not use water and the like. As a result, the nonmagneticlayer 19 contains more hydrogen (H) than the gap layer 16.

The foregoing difference in the composition and hydrogen content of thenonmagnetic layer 19 is applicable not only to the gap layer 16 but alsoto the insulating layers 12 and 13, the nonmagnetic layer 15, theovercoat layer 24, etc. which may be made of the same nonmagneticinsulation materials as of the gap 16.

The thin film coil 21 generates write magnetic flux. Currents flow inthe thin film coil 21 in a direction opposite to that of the thin filmcoil 10, for example. Other configuration of the thin film coil 21 isthe same as that of thin film coil 10 except the above-described matter,for example.

The insulating layer 20 is a base of the thin film coil 21, which ismade of the same nonmagnetic insulation material as the insulating layer12 for example. The insulating layer 22 covers the insulating layer 20together with the thin film coil 21, which is made of the samenonmagnetic insulation material as the insulating layer 11 for example.These are disposed in such a manner that the back gap BG are notcovered, and they are connected with the nonmagnetic layer 19. The frontedge of the insulating layer 22 is being recessed from the front edge ofthe nonmagnetic layer 19, for example.

The return yoke layer 23, which extends from the air bearing surface 40to backward, has a function of circulating the magnetic flux between thethin film magnetic head and the write medium 50 by collecting thewritten magnetic flux (magnetic flux used for write processing in thewrite medium 50) and resupplying it to the main magnetic pole layer 14and the auxiliary magnetic pole layer 17. The return yoke layer 23 ismagnetically connected with the write shield layer 18 on a side close tothe air bearing surface 40, for example, while it is magneticallyconnected with the auxiliary magnetic pole layer 17 on a side far fromthe air bearing surface 40. In addition, the return yoke layer 23 ismade of the same magnetic material as the write shield layer 18, forexample, and is of a rectangle configuration in plan view with a widthW3 as shown in FIG. 2. The end faces of the write shield layer 18 andthe return yoke layer 23 are of a rectangle configuration, for example,as shown in FIG. 3.

It is to be noted that the write medium 50 includes a magnetizationlayer 51 and a soft magnetic layer 52 in order from the side close tothe thin film magnetic head, for example, as shown in FIG. 4. Themagnetization layer 51 works to write information magnetically, and thesoft magnetic layer 52 functions as a passage of the magnetic flux (whatis called flux pass) in the write medium 50. Such kind of mediumstructure is called double layer perpendicular magnetic medium. It isneedless to say that the write medium 50 may include other layers thanthe above-mentioned magnetization layer 51 and the soft magnetic layer52.

The thin film magnetic head is operated as follows.

Namely, when a current flows into the thin film coil 21 of the writehead section 100B from a not-illustrated external circuit at the time ofinformation writing, a write magnetic flux J is generated. The magneticflux J, after accommodated in the main magnetic pole layer 14 and theauxiliary magnetic pole layer 17, flows through the inside of the mainmagnetic pole layer 14 to the tip portion 14A. At that time, themagnetic flux J converges by being narrowed down at the flare point FP,thereby being concentrated around the trailing edge TE. The magneticflux J is emitted outside to generate a perpendicular magnetic field,and then the magnetization layer 51 is magnetized by the generatedperpendicular magnetic field. As a result, information is magneticallywritten on the write medium 50.

In this case, since currents flows into the thin film coils 10 and 21 ina mutually opposite direction, magnetic flux of a mutually oppositedirection is generated respectively. Specifically, an upward magneticflux is generated in the thin film coil 10 for controlling leakage,while a downward write magnetic flux is generated in the thin film coil21. In response to the influence of the magnetic flux for leakagecontrol, accordingly, the write magnetic flux hardly flows from thewrite head section 100B into the read head section 100A. Thereforeleakage of the write magnetic flux is suppressed. As a result,deterioration of detecting accuracy of the MR element 8 caused by theinfluence of the write magnetic flux can be suppressed, and further,unintended erasure of information written on the write medium 50, whichis due to a generation of unnecessary magnetic field caused by taking inthe write magnetic flux into the lower read shield layer 3 and the upperread shield layer 30, can be suppressed.

In addition, when the magnetic flux J is emitted from the tip portion14A, spread components of the magnetic flux J is taken into the writeshield layer 18 to suppress the spread of the perpendicular magneticfield. The magnetic flux J taken into the write shield layer 18 isresupplied to the main magnetic pole layer 14 and the auxiliary magneticpole layer 17 via the return yoke layer 23.

The magnetic flux J emitted from the main magnetic pole layer 14 towardthe write medium 50 is collected by the return yoke 23 via the softmagnetic layer 52 after magnetizing the magnetization layer 51. In thiscase, a part of the magnetic flux J is collected also by the writeshield layer 18. The magnetic flux J collected by those is resupplied tothe main magnetic pole layer 14 and the auxiliary magnetic pole layer17. Accordingly, since the magnetic flux J circulates between the writehead section 100B and the write medium 50, a magnetic circuit is built.

On the other hand, when a sense current flows into the MR element 8 ofthe read head section 100A at the time of information reading,resistance of the MR element 8 changes in accordance with the readsignal magnetic field from the write medium 50. The information writtenon the write medium 50 is read magnetically by detecting this resistancechange as a voltage change.

Next, a method of manufacturing the above-described thin film magnetichead will be explained with reference to FIGS. 1A and 1B to FIG. 8.FIGS. 5A and 5B to FIGS. 8A and 8B illustrate a manufacturing process ofthe thin film magnetic head, showing cross-sectional configurationscorresponding to FIGS. 1A and 1B respectively. Hereinbelow, first, amanufacturing process of the whole thin film magnetic head isschematically explained, then a formation process of the principalportions of the write head section 100B is explained in detail. Sinceconfiguration of the series of component elements, which constitute thethin film magnetic head, has already been explained in detail, thedescription thereof will be omitted as needed. The thin film magnetichead is manufactured by forming and layering the series of componentelements successively with an existing thin film process, mainly using afilm formation technique represented by electroplating methods orsputtering, a patterning technique represented by photo lithographymethods, an etching technique represented by dry etching methods or wetetching methods, and a planarization technique represented by polishingmethods and so on. Namely, as shown in FIGS. 1A and 1B, after formingthe insulating layer 2 on the substrate 1 first, the read head section100A is formed by layering on the insulating layer 2 the lower readshield layer 3, the shield gap layer 4 in which the MR element 8 isburied, and the upper read shield layer 30 (the upper read shield layerportions 5 and 7, and the nonmagnetic layer 6) in this order.Subsequently, after forming the separation layer 9 on the read headsection 10A, the write head section 100B is formed by layering on theseparation layer 9 the thin film coil 10 buried in the insulating layers11 to 13, the main magnetic pole layer 14 with its periphery buried bythe nonmagnetic layer 15, the gap layer 16, the auxiliary magnetic polelayer 17 with its periphery buried by the nonmagnetic layer 19, thewrite shield layer 18, the thin film coil 21 buried within theinsulating layers 20 and 22, and the return yoke layer 23 in this order.Finally, after forming the overcoat layer 24 on the write head section100B, the air bearing surface 40 is formed using machining or polishprocessing, thereby completing the formation of the thin film magnetichead.

Formation of the principal portion of the write head section 100B iscarried out in such a manner that, after forming the insulating layer13, as shown in FIGS. 5A and 5B, the main magnetic pole layer 14 isfirst formed on the insulating layer 13 by frame electroplating, forexample. In this case, the main magnetic pole layer 14 is made to have aspecified internal stress (for example, tensile stress). An example ofdetailed fabrication procedures of the main magnetic pole layer 14 byframe electroplating is as follows. Namely, first, a seed layer as anelectrode film is formed on the insulating layer 13 using sputtering forexample. Subsequently, after applying photoresist to the face of theinsulating layer 13 to form a photoresist film thereon, a photoresistpattern is formed as a frame for plating by patterning the photoresistfilm using a photo lithography method (exposure and development).Subsequently, the main magnetic pole layer 14 is formed by growing up aplating film selectively on the seed layer using the photoresistpattern. Finally, after removing the photoresist pattern, an unnecessaryportion of the seed layer is removed selectively using ion milling etc.

Subsequently, the nonmagnetic layer 15 is buried on the periphery of themain magnetic pole layer 14. Details of the burial procedure will bementioned later exemplified by a case of the nonmagnetic layer 19.Subsequently, the gap layer 16 is formed on the main magnetic pole layer14 and the nonmagnetic layer 15 by sputtering for example. In this case,a portion other than the area in which the auxiliary magnetic pole layer17 is to be formed by a post-production process is covered by the gaplayer 16, therefore the main magnetic pole layer 14 is partiallyexposed. Subsequently, the auxiliary magnetic pole layer 17 is formed onthe exposure of the main magnetic pole layer 14 by frame electroplatingfor example, and also the write shield layer 18 is formed on the gaplayer 16. In this case, the auxiliary magnetic pole layer 17 and thewrite shield layer 18 may be formed in the same production process, orthey may be formed in a production process.

Subsequently, the nonmagnetic layer 19 is formed so as to cover the gaplayer 16, the auxiliary magnetic pole layer 17 and the write shieldlayer 18 by the ALD method for example, as shown in FIGS. 6A, 6B. Inthis case, the nonmagnetic layer 19 is to be embedded between theauxiliary magnetic pole layer 17 and the write shield layer 18 at least,and also, the nonmagnetic layer 19 is made to have the internal stressin a direction same as that of the main magnetic pole layer 14 (forexample, tensile stress). It is to be noted that the substratetemperature of the ALD method is the same as that of the ordinarysubstrate temperature, specifically about 150 degrees C. or more, andpreferably about 200 degrees C.

Subsequently, the nonmagnetic layer 19 is selectively removed until theauxiliary magnetic pole layer 17 is exposed at least and the wholeconfiguration is made flat as shown in FIGS. 7A, 7B, thereby filling upa space between the auxiliary magnetic pole layer 17 and the writeshield layer 18 with the nonmagnetic layer 19. In this case, flatteningmay be carried out using a polishing method such as chemical mechanicalpolishing (CMP), or an etching method such as ion milling or reactiveion etching (RIE). Among them, the polishing method is preferred inorder to increase surface smoothness through a rather simple productionprocess. The flattening procedure may be completed when the auxiliarymagnetic pole layer 17 is exposed, or may be continued even after theexposure of the auxiliary magnetic pole layer 17 so as to adjust/obtaina desirable thickness thereof.

Subsequently, after forming the insulating layer 20 by sputtering forexample, on the foregoing flattened face, the thin film coil 21 isformed on the insulating layer 20 by frame electroplating for example asshown in FIGS. 8A and 8B. In this case, position of the insulating layer20 is adjusted so as to cover the area where the thin film coil 21 is tobe formed in a post-production process. Subsequently, the insulatinglayer 22 is formed so as to cover the insulating layer 20, the thin filmcoil 21 and also their peripheral region. In this case, for example,photoresist is applied and then heated until it flows backward, so thatits front edge retreats rather than that of the nonmagnetic layer 19.

Finally, the return yoke layer 23 is formed by frame electroplatingmethod for example on the auxiliary magnetic pole layer 17, the writeshield layer 18, and the insulating layer 22. In this manner, theprincipal portion of the write head section 100B is thereby completed.

In the thin film magnetic head and method of manufacturing the sameaccording to the present embodiment, when the main magnetic pole layer14 having a specified internal stress and the auxiliary magnetic polelayer 17 disposed on the trailing side of the main magnetic pole layer14 in a position being recessed from that are provided, the nonmagneticlayer 19, which is disposed in a layer same as the auxiliary magneticpole layer 17 and in an area in front of the layer, and which has aninternal stress of a direction same as that of the main magnetic polelayer 14, is provided. With this arrangement, unintended erasure ofinformation written on the write medium 50 can be suppressed at anon-writing time, by optimizing the magnetic domain structures of themain component elements that are engaged in writing operation for thefollowing reasons.

FIGS. 9 and 10 express magnetic domain structures of the main magneticpole layer 14, and FIG. 9 shows a case of the present embodiment andFIG. 10 shows a case of a comparative example respectively. FIG. 11shows magnetic domain structures of the auxiliary magnetic pole layer 17and the write shield layer 18 in the present embodiment. The thin filmmagnetic head of the comparative example has the same configuration asthat of the thin film magnetic head of the present embodiment exceptthat it has an internal stress of a direction opposite to that of themain magnetic pole layer 14 because the nonmagnetic layer 19 is formedby sputtering and so on.

As for the latest head design, there is a tendency that thickness of themain magnetic pole layer 14 becomes increasingly thinner in order torealize high writing density by narrowing a track pitch. Accordingly, inorder to secure quantity of the write magnetic flux, there is a tendencythat the auxiliary magnetic pole layer 17, whose thickness is enlargedenough, is disposed together with the main magnetic pole layer 14. Withsuch arrangement, the thickness of the nonmagnetic layer 19, which isdisposed in a layer same as the auxiliary magnetic pole layer 17,naturally tends to be enlarged. In this case, the internal stress of thenonmagnetic layer 19, which is in the vicinity of the main magnetic polelayer 14 via the thin gap layer 16, will increase when the thickness ofthe nonmagnetic layer 19 is enlarged. As a result, there is a problemthat the magnetic domain structure of the main magnetic pole layer 14 isinfluenced by the internal stress of the nonmagnetic layer 19.

In the comparative example, the nonmagnetic layer 19 has the internalstress of a direction opposite to that of the main magnetic pole layer14. Therefore, the magnetic domain structure of the main magnetic polelayer 14 is deteriorated due to the influence of the internal stress ofthe nonmagnetic layer 19.

Specifically, as shown in FIG. 10, the magnetic domain structure of themain magnetic pole layer 14 is that the occupancy rate of amagnetization component 14Y, which is along the emission direction ofthe magnetic flux at the time of writing (Y-axis direction), is largerthan the occupancy rate of a magnetization component 14X, which crosses(orthogonal) to the emission direction of the magnetic flux (X-axisdirection). As a result, magnetic flux which remains in the mainmagnetic pole layer 14 is easily leaked out immediately afterinformation-writing due to the magnetoelasticity effect, which occursdue to the magnetic domain structure in which the magnetizationcomponent 14Y is dominant. Accordingly, the magnetic domain structure ofthe main magnetic pole layer 14 is not optimized and therefore itbecomes difficult to suppress unintended erasure of information writtenon the write medium 50 at a non-writing time.

In the present embodiment, on the other hand, the nonmagnetic layer 19has the internal stress in a direction same as that of the main magneticpole layer 14. Therefore, the magnetic domain structure of the mainmagnetic pole layer 14 is kept in a good state of the initial formationwithout being influenced by the internal stress of the nonmagnetic layer19. Specifically, as shown in FIG. 9, the magnetic domain structure ofthe main magnetic pole layer 14 is that, unlike the case of thecomparative example, the occupancy rate of the magnetization component14X is larger than that of the magnetization component 14Y. As a result,magnetic flux which remains in the main magnetic pole layer 14 is hardlyleaked out immediately after information-writing due to themagnetoelasticity effect.

Moreover in this case, not only the magnetic domain structure of themain magnetic pole layer 14 but also the magnetic domain structures ofboth of the auxiliary magnetic pole layer 17 and the write shield layer18 can be kept in a good state without being influenced by the internalstress of the nonmagnetic layer 19. Specifically, as shown in FIG. 11,the magnetic domain structure of the auxiliary magnetic pole layer 17 isthat the occupancy rate of a magnetization component 17X is larger thanthat of a magnetization component 17Y, according to the same operationas in the case of the magnetic domain structure of the main magneticpole layer 14. As well, the magnetic domain structure of the writeshield layer 18 is that the occupancy rate of a magnetization component18X is larger than that of a magnetization component 18Y.

Accordingly, the magnetic domain structures of the main magnetic polelayer 14, the auxiliary magnetic pole layer 17, and the write shieldlayer 18 are optimized in the present embodiment. As a result,unintended erasure of information written on the write medium 50 can besuppressed at a non-writing time, by optimizing the magnetic domainstructures of the main component elements that are engaged in writingoperation.

Hereinafter, on behalf of the main magnetic pole layer 14, the auxiliarymagnetic pole layer 17, and the write shield layer 18, the principle ofoptimization for the magnetic domain structure of the main magnetic polelayer 14 will be explained with a specific example, which is as follows.

When a magnetic material having a positive magnetostriction constant isused as the component material of the main magnetic pole layer 14, itwill have a tensile stress as its internal stress. In this case, if themagnetostriction constant is λ, the stress is σ, and the magnetizationis M, a magnetic field H induced by the internal stress in the mainmagnetic pole layer 14 is expressed as H=3λ (σ/M) as a relation betweenthe internal stress of the main magnetic pole layer 14 and the magneticdomain structure. The easy magnetization directions of the main magneticpole layer 14 are in agreement with the direction of the tensile stress,when the tensile stress is given in a direction parallel to the airbearing surface 40. It is deduced from the fact that a tensile stress ispreferred as the internal stress of the main magnetic pole layer 14.

As an example, if an iron-cobalt based alloy, whose saturation magneticflux density is 2.2 T (tesla) or more is used as a component material ofthe main magnetic pole layer 14, the magnetostriction constant λ of themain magnetic pole layer 14 will become 20×10⁻⁶ or more, and a tensilestress of 400 MPa or more will be generated as internal stress. On theother hand, if an aluminum oxide is used as a formation material of thenonmagnetic layer 19 and sputtering is used as its formation method, acompressive stress of about 100 MPa or less will be generated asinternal stress. In view of those described above, since Young's modulusand Poisson's ratio of the iron-cobalt based alloy are 121 GPa and 0.25respectively, while Young's modulus and Poisson's ratio of the aluminumoxide are 150 GPa and 0.3 respectively, the internal stress, which isproduced in the nonmagnetic layer 19, has a direction opposite to thatof the internal stress (tensile stress) produced in the main magneticpole layer 14, namely, it becomes a compressive stress.

In the present embodiment, since the ALD method is used in the formationof the nonmagnetic layer 19, unlike the case where sputtering is used, atensile stress of about 200 MPa to 300 MPa is generated in thenonmagnetic layer 19. Accordingly, the magnetic domain structure of themain magnetic pole layer 14 is kept in a good state without beinginfluenced by the internal stress of the nonmagnetic layer 19 asdescribed above. Therefore the magnetic domain structure is optimized sothat residual flux in the main magnetic pole layer 14 may hardly beleaked out immediately after information-writing due to themagnetoelasticity effect.

In addition, in the present embodiment, the auxiliary magnetic polelayer 17 is disposed on the trailing side of the main magnetic polelayer 14. As a result, unlike a case where the auxiliary magnetic polelayer 17 is disposed on the leading side of the main magnetic pole layer14, unintended erasure of information can be suppressed at the time ofwriting, for the following reasons.

In order to increase intensity of the perpendicular magnetic field, itis preferred to dispose the auxiliary magnetic pole layer 17 having alarge magnetic volume as close as possible to the air bearing surface 40so that the amount of magnetic flux supplied to the tip portion 14A ofthe main magnetic pole layer 14 can be increased. However, if theauxiliary magnetic pole layer 17 is disposed close to the air bearingsurface 40 too much, magnetic flux in the auxiliary magnetic pole layer17 is easily emitted directly outside, not through the main magneticpole layer 14 at the time of writing. So there is a concern thatinformation may be easily erased without intention due to the magneticflux. When the auxiliary magnetic pole layer 17 is disposed on theleading side of the main magnetic pole layer 14, magnetic substance fortaking in the magnetic flux does not exist in front of the auxiliarymagnetic pole layer 17. With this arrangement, information is easilyerased due to the magnetic flux directly emitted outside from theauxiliary magnetic pole layer 17. On the other hand, when the auxiliarymagnetic pole layer 17 is disposed on the trailing side of the mainmagnetic pole layer 14, the write shield layer 18 and the return yokelayer 23, which are magnetic substances for taking in the magnetic flux,are disposed in front of the auxiliary magnetic pole layer 17. With thisarrangement, even when magnetic flux is nearly emitted directly outsidefrom the auxiliary magnetic pole layer 17, the magnetic flux can betaken in by the write shield layer 18 and the return yoke layer 23. Inthis manner, unintended erasure of information at the time of writingcan be thereby prevented.

In this case, if the auxiliary magnetic pole layer 17 is brought closerto the air bearing surface 40, the space between the auxiliary magneticpole layer 17 and the write shield layer 18 is narrowed, andconsequently it becomes difficult to fill up the space with thenonmagnetic layer 19. In view of that, the present embodiment adopts theALD method as a formation method of the nonmagnetic layer 19, which isadvantageous to a precise membrane formation. As a result, in thepresent embodiment, unlike the case where methods that aredisadvantageous to a precise membrane formation such as sputtering isused, not only can the nonmagnetic layer 19 be formed so as to have atensile stress as its internal stress, but the nonmagnetic layer 19 canprecisely fill up a narrow space between the auxiliary magnetic polelayer 17 and the write shield layer 18.

Although only the nonmagnetic layer 19 disposed in a layer same as theauxiliary magnetic pole layer 17 is made to have an internal stress of adirection same as that of the main magnetic pole layer 14 in the presentembodiment, it is not necessarily restricted to that, and othernonmagnetic layers (layers made of any nonmagnetic substance) disposedin a layer different from that of the auxiliary magnetic pole layer 17may have a similar internal stress. Examples of “other nonmagneticlayers” described above include the insulating layer 13, the nonmagneticlayer 15, and the gap layer 16 disposed in the vicinity of the mainmagnetic pole layer 14. Since thicknesses of those layers are remarkablythinner than the thickness of the nonmagnetic layer 19, their internalstresses have little effect on the magnetic domain structure of the mainmagnetic pole layer 14. Accordingly, the magnetic domain structure ofthe main magnetic pole layer 14 will be optimized in many cases if thenonmagnetic layer 19 has a proper internal stress. However, in order toreliably suppress the influence exerted on the magnetic domain structureof the main magnetic pole layer 14 by the internal stresses of theinsulating layer 13, the nonmagnetic layer 15, and the gap layer 16, itis preferred that they also have the same internal stress as that of thenonmagnetic layer 19. All of the insulating layers 13, the nonmagneticlayers 15, and the gap layers 16 may have the same internal stress asthat of the nonmagnetic layer 19, or only some of them may have. In thiscase, as compared with a case where only the nonmagnetic layer 19 hasthe internal stress of the same direction as that of the main magneticpole layer 14, the magnetic domain structure of the main magnetic polelayer 14 can be optimized with much stability.

Further, in the present embodiment, although both of the thin film coils10 and 21 are provided, it is not necessarily limited to that, and onlythe thin film coil 21 may be provided. In this case, as with the thinfilm coil 10, the insulating layers 11 to 13 for burying the thin filmcoil 10 will also become unnecessary. With this arrangement, effectssimilar to the foregoing embodiment can be obtained.

Second Embodiment

Next, configuration of a thin film magnetic head according to a secondembodiment of the present invention will be described. FIGS. 12A and 12Billustrate configurations of a thin film magnetic head, showingcross-sectional configurations corresponding to FIGS. 1A and 1Brespectively. FIGS. 13A and 13B to 17A and 17B are views for explaininga manufacturing process of the thin film magnetic head, showingcross-sectional configurations corresponding to FIGS. 12A and 12Brespectively. In FIGS. 12A and 12B to 17A and 17B, the same referencenumerals are given to the same component elements as those shown in thefirst embodiment.

In the thin film magnetic head according to the present embodiment,unlike the first embodiment in which the auxiliary magnetic pole layer17 is located on the trailing side of the main magnetic pole layer 14,an auxiliary magnetic pole layer 91 is located on the leading side ofthe main magnetic pole layer 14. Such structure as the auxiliarymagnetic pole layer 91 is located on the leading side is called bottomyoke structure. This thin film magnetic head is configured in the samemanner as the thin film magnetic head of the first embodiment exceptthat, for example, as shown in FIGS. 12A and 12B, (1) the auxiliarymagnetic pole layer 91 with its periphery buried by a nonmagnetic layer92 is provided between the insulating layer 13 and the main magneticpole layer 14; (2) a connection layer 93 is provided in a layer wherethe auxiliary magnetic pole layer 17 was disposed, on the area where theback gap BG is provided; and (3) a space between the write shield layer18 and the connection layer 93 is filled up with a nonmagnetic layer 94.

The auxiliary magnetic pole layer 91 has the same function and sameconfiguration as the auxiliary magnetic pole layer 17, and thenonmagnetic layer 92 has the same configuration as the nonmagnetic layer19. Namely, when the main magnetic pole layer 14 has the internal stressof a specified direction (for example, tensile stress), the nonmagneticlayer 92 disposed in a layer same as the auxiliary magnetic pole layer91 and in an area in front of the layer has the internal stress of thesame direction as that of the main magnetic pole layer 14 (for example,tensile stress) because it is formed by the ALD method and so on.

The connection layer 93 is a layer magnetically connecting the mainmagnetic pole layer 14 and the return yoke layer 23. At the time of theoperation of the thin film magnetic head, the magnetic flux taken in bythe return yoke layer 23 is resupplied to the main magnetic pole layer14 and the auxiliary magnetic pole layer 91 via the connection layer 93.

The nonmagnetic layer 94 has the same function as the nonmagnetic layer19. The nonmagnetic layer 94 may have the internal stress of the samedirection as that of the main magnetic pole layer 14 as with thenonmagnetic layer 19, or may have the internal stress of a directionopposite to that. It is because, in many cases, the magnetic domainstructure of main magnetic pole layer 14 can be optimized if only thenonmagnetic layer 92 has the internal stress of the same direction asthat of the main magnetic pole layer 14 as described above, even if thenonmagnetic layer 94 does not have the internal stress of the samedirection as the main magnetic pole layer 14. Further, it is because thethickness (magnetic volume) of the write shield layer 18 and theconnection layer 93 does not need to be so large as that of theauxiliary magnetic pole layer 91, and therefore the thickness of thenonmagnetic layer 94 may be comparatively thin. As a result, influenceexerted by the internal stress of the nonmagnetic layer 94 on themagnetic domain structure of the main magnetic pole layer 14 is small.However, in order to reliably suppress the influence exerted by theinternal stresses of the nonmagnetic layer 94 on the magnetic domainstructure of the main magnetic pole layer 14, it is preferred that thenonmagnetic layer 94 also has the same internal stress as that of thenonmagnetic layer 92.

The thin film magnetic head is manufactured by the same procedure as thefirst embodiment except the points as explained below. Upon forming aprincipal portion of the write head section 100B, after formation of theinsulating layer 13, the auxiliary magnetic pole layer 91 is formed onthe insulating layer 13 by frame electroplating for example, then thenonmagnetic layer 92 is formed by the ALD method for example so as tocover the auxiliary magnetic pole layer 91 and the insulating layer 13disposed in the periphery thereof, as shown in FIGS. 13A, 13B. In thiscase, the nonmagnetic layer 92 is to be embedded in front of theauxiliary magnetic pole layer 91 at least, and to have the internalstress (for example, tensile stress) of the same direction as that ofthe main magnetic pole layer 14, which will be formed in apost-production process.

Subsequently, the nonmagnetic layer 92 is selectively removed until atleast the auxiliary magnetic pole layer 91 is exposed to make the wholeconfiguration flat, thereby embedding the nonmagnetic layer 92 in theperiphery of the auxiliary magnetic pole layer 91 as shown in FIGS. 14Aand 14B.

Subsequently, as shown in FIGS. 15A and 15B, the main magnetic polelayer 14 is formed on the above-described flattened face by frameelectroplating for example. In this case, the main magnetic pole layer14 is made to have a specified internal stress (for example, tensilestress). Subsequently, after forming the gap layer 16 on the mainmagnetic pole layer 14 by sputtering for example, the connection layer93 is selectively formed on an exposure of the main magnetic pole layer14 by frame electroplating for example, and the write shield layer 18 isformed on the gap layer 16. In this case, the connection layer 93 andthe write shield layer 18 may be formed in a same production process, orthey may be formed in a separate production process. Subsequently, thenonmagnetic layer 94 is formed so that the main magnetic pole layer 14,the gap layer 16, the connection layer 93, and the write shield layer 18may be all covered. In this case, the nonmagnetic layer 94 is made to beembedded between the connection layer 93 and the write shield layer 18at least. As for a formation method of the nonmagnetic layer 94, the ALDmethod or the like may be used in order to have the internal stress ofthe same direction as that of the main magnetic pole layer 14, orsputtering or the like may be used in order to have the internal stressof a direction opposite to that.

Subsequently, the nonmagnetic layer 94 is selectively removed until theconnection layer 93 is exposed at least to make the whole configurationflat, as shown in FIGS. 16A and 16B, thereby filling up a space betweenthe connection layer 93 and the write shield layer 18 with thenonmagnetic layer 94.

Subsequently, as shown in FIGS. 17A and 17B, the thin film coil 21buried in the insulating layer 20, 22 and the return yoke layer 23 areformed in accordance with a procedure explained with reference to FIGS.8A and 8B. Specifically, the insulating layer 20 is formed on the flatface after the above-mentioned flattening process, then, after formingthe thin film coil 21 on the insulating layer 20, the insulating layer22 is formed so as to cover the insulating layer 20, the thin film coil21 and its peripheral region. After this, the return yoke layer 23 isselectively formed on the connection layer 93, the write shield layer 18and the insulating layer 22. In this manner, the principal portion ofthe write head section 100B is completed.

In the thin film magnetic head and method of manufacturing the sameaccording to the present embodiment, when the main magnetic pole layer14 having a specified internal stress and the auxiliary magnetic polelayer 91 disposed on the leading side of the main magnetic pole layer 14in a position being recessed from that are provided, the nonmagneticlayer 92, which is disposed in a layer same as the auxiliary magneticpole layer 91 and in an area in front of the layer and which has theinternal stress of the same direction as that of the main magnetic polelayer 14, is provided. With this arrangement, the magnetic domainstructure of the main magnetic pole layer 14 is kept in a good state ofthe initial formation without being influenced by the internal stress ofthe nonmagnetic layer 92 in accordance with the same operation as thefirst embodiment. Accordingly, unintended erasure of information writtenon the write medium 50 can be suppressed at a non-writing time byoptimizing magnetic domain structures of the main component elementsthat are engaged in writing operation.

In particular, in the present embodiment, the magnetic domain structureof the main magnetic pole layer 14 can be optimized with much stabilityif not only the nonmagnetic layer 92 but also the nonmagnetic layer 94are made to have the internal stress of the same direction as that ofthe main magnetic pole layer 14.

It is to be noted that the operations, effects, and modifications of thepresent embodiment are the same as those of the foregoing firstembodiment except for the points described above.

Next, a configuration of a magnetic write system which carries theabove-mentioned thin film magnetic head will be explained. FIGS. 18 and19 illustrate the configuration of the magnetic write system, and, FIG.18 illustrates a whole perspective configuration thereof and FIG. 19illustrates a perspective configuration of the principal portionrespectively.

As shown in FIG. 18, this magnetic write system, which is a hard diskdrive for example, includes within a case 200: a plurality of magneticdisks (for example, hard disk) 201 corresponding to the write medium 50(reference to FIG. 4); a plurality of suspensions 203, each of themarranged corresponding to the magnetic disk 201 to support a magnetichead slider 202 at one ends thereof; and a plurality of arms 204, eachof them supporting the other end of the suspension 203. The magneticdisk 201 can rotate around a spindle motor 205 which is fixed to thecase 200. The arm 204 is connected with a driving section 206 as a powersource, and can turn with respect to a fixed axle 207 which is fixed tothe case 200 via a bearing 208. The driving section 206 includes suchdriving sources as a voice coil motor, for example. This magnetic writesystem is a model in which the plurality of arms 204 can turn integrallywith respect to the fixed axle 207, for example. It is to be noted thatthe case 200 is partially cut out to easily show the internal structureof the magnetic write system in FIG. 18.

The magnetic head slider 202 is configured in such a manner that, asshown in FIG. 19 for example, a thin film magnetic head 212 is attachedto one side of a base 211, which is of an abbreviated rectangularparallelepiped in shape and which is made of nonmagnetic insulationmaterials such as altic. One side (that is, an air bearing surface 220)of this base 211 is formed unevenly for example for decreasing airresistance produced at the time of the turn of the arms 204. And thethin film magnetic head 212 is attached to another side orthogonal tothe air bearing surface 220 (in this case, the front right side in FIG.19). This thin film magnetic head 212 has the configuration explained ineach of the above-mentioned embodiments. The magnetic head slider 202,when the magnetic disk 201 rotates at the time of information writing orreading, lifts up from the writing surface of the magnetic disk 201(surface opposed to the magnetic head slider 202) using an airflowproduced between the writing surface of the magnetic disk 201 and theair bearing surface 220. It is to be noted that in FIG. 19, the magnetichead slider 202 is illustrated in an upside-down state compared withthat of FIG. 18, in order to easily show the structure on the side ofthe air bearing surface 220 of the magnetic head slider 202.

In this magnetic write system, the arm 204 turns at the time ofinformation writing or reading so that the magnetic head slider 202 canmove to a specified area of the magnetic disk 201 (write area). And whenthe thin film magnetic head 212 is connected electrically in such astate as opposed to the magnetic disk 201, the thin film magnetic head212 carries out write or read processing to the magnetic disk 201 basedon the above-mentioned operation principal.

In this magnetic write system, since the above-mentioned thin filmmagnetic head is arranged, unintended erasure of information written onthe magnetic disk 201 can be suppressed at a non-writing time.

Next, examples of the present invention will be explained hereinbelow.

When the write performance of the thin film magnetic head that has a topyoke structure (reference to FIGS. 1A and 1B to FIG. 4) of the firstembodiment was investigated on behalf of the thin film magnetic headsexplained in the first and second embodiments, such results as shown inFIG. 20 were obtained. FIG. 20 shows a write width dependency of writesignal deterioration on a write width, the horizontal direction showinga write width W (μm), and the vertical direction showing a signalstrength ratio S (−), respectively. The write width expresses a width ofa writing track on the write medium 50.

As for the component material, the thickness, and the formation method(internal stress) of the main component elements of the thin filmmagnetic head upon investigating the deterioration state of the writesignal, the following conditions were adopted respectively: the mainmagnetic pole layer 14: iron, cobalt alloy, 0.25 μm, and frameelectroplating method (tensile stress), the gap layer 16: alumina, 0.04μm, and sputtering method (compressive stress), the auxiliary magneticpole layer 17: permalloy, 0.8 μm, and frame electroplating method(tensile stress), the write shield layer 18; permalloy, 0.76 μm, andframe electroplating method (tensile stress) the nonmagnetic layer 19:alumina, 0.76 μm, and the ALD method (tensile stress).

Procedure of investigating the deterioration state of the write signalsby use of the thin film magnetic head was as follows: write processingwas carried out to the write medium 50 in a writing state (a state inwhich the thin film coil 21 was energized), then after tracing the writemedium 50 in a non-writing state (a state in which the thin film coil 21was not energized) as with the case of writing state, the readprocessing was carried out to the write medium 50. At that time, anintensity S1 of the write signal before tracing and an intensity S2 ofthe read signal after tracing were investigated and thereby, the signalstrength ratio S (=S2/S1) was calculated. This signal strength ratio Sis a parameter indicative of an attenuance of the write signalbefore/after the tracing, namely, how easy it is to erase informationwithout intention at a non-writing time.

In addition, upon investigating the deterioration state of the writesignal about the thin film magnetic head of the present invention,deterioration state of the write signal was investigated also about thethin film magnetic head of the comparative example described in thefirst embodiment, in which the nonmagnetic layer 19 had a compressivestress, in order to make a comparative evaluation thereof. In this case,component material, thickness, and formation method of the nonmagneticlayer 19 were alumina, 0.76 μm, and sputtering method respectively. FIG.20 also shows a result of the comparative example together with theresult of the present invention, and ● is of the present invention and ▪is of the comparative example respectively.

As known by the results shown in FIG. 20, in the comparative example,when the write width W was varied within a range of 0.138 μm to 0.164μm, the signal strength ratio S was distributed over a wide range ofabout 0.09 to 1. On the other hand, in the present invention, when thewrite width W was varied within a range of 0.148 μm to 0.166 μm, thesignal strength ratio S was distributed over a narrow range of 0.87to 1. The foregoing results mean that the write signal is maintainedwith ease in the present invention compared with that of the comparativeexample, namely, that information is hardly erased at a non-writingtime. In view of the above, it was confirmed that in the thin filmmagnetic head of the present invention, unintended erasure ofinformation written on write medium 50 can be suppressed at anon-writing time.

Although the present invention has been described above with referenceto the embodiments and examples, the invention is not limited to theembodiments but can be variously modified. For example, although theabove-mentioned embodiments have explained the combined magnetic writeand read head as a structure of the thin film magnetic head, it is notnecessarily restricted to this, and the perpendicular magnetic writehead of the present invention can be applied to a write-only head havingan induction type magnetic transducer element for write, and also to awrite and read head having an induction type magnetic transducer elementfor both of writing and reading. It is needless to say that theperpendicular magnetic write head of the present invention is applicablealso to a head configured in such a manner that stacking sequence of awrite element and a read element are reversed.

1. A perpendicular magnetic write head, comprising: a main magnetic polelayer leading a magnetic flux to a write medium, the main magnetic polelayer having an internal stress of a specified direction; an auxiliarymagnetic pole layer disposed on a trailing side of the main magneticpole layer, the auxiliary magnetic pole layer being recessed from themain magnetic pole layer; a nonmagnetic layer disposed in a layer sameas the auxiliary magnetic pole layer and in front of the auxiliarymagnetic pole layer, the nonmagnetic layer having an internal stress ofa direction same as that of the main magnetic pole layer; and a writeshield layer disposed in a layer same as the auxiliary magnetic polelayer and in front of the auxiliary magnetic pole layer, the writeshield layer being separated from the main magnetic pole layer with agap layer in between, wherein the nonmagnetic layer is arranged to fillup a space between the auxiliary magnetic pole layer and the writeshield layer.
 2. The perpendicular magnetic write head according toclaim 1, wherein both the main magnetic pole layer and the nonmagneticlayer have a tensile stress.
 3. The perpendicular magnetic write headaccording to claim 1, wherein the nonmagnetic layer is formed by ALD(atomic layer deposition) method.
 4. The perpendicular magnetic writehead according to claim 1, wherein the nonmagnetic layer is made ofAluminum Oxide (AlO_(x)) or Aluminum Nitride (AlN).
 5. A perpendicularmagnetic write head, comprising: a main magnetic pole layer leading amagnetic flux to a write medium, the main magnetic pole layer having aninternal stress of a specified direction; an auxiliary magnetic polelayer disposed on a leading side of the main magnetic pole layer, theauxiliary magnetic pole layer being recessed from the main magnetic polelayer; a nonmagnetic layer disposed in a layer same as the auxiliarymagnetic pole layer and in front of the auxiliary magnetic pole layer,the nonmagnetic layer having an internal stress of a direction same asthat of the main magnetic pole layer; a write shield layer disposed onthe trailing side of the main magnetic pole layer in an area close to anairbearing surface, the write shield layer being separated from the mainmagnetic pole layer with a gap layer in between; and another nonmagneticlayer disposed in a layer same as the write shield layer at the back ofthe write shield layer, the another nonmagnetic layer having an internalstress of a direction same as that of the main magnetic pole layer. 6.The perpendicular magnetic write head according to claim 5, wherein boththe main magnetic pole layer and the nonmagnetic layer have a tensilestress.
 7. The perpendicular magnetic write head according to claim 5,wherein the nonmagnetic layer is formed by ALD (atomic layer deposition)method.
 8. The perpendicular magnetic write head according to claim 5,wherein the nonmagnetic layer is made of Aluminum Oxide (AlO_(x)) orAluminum Nitride (AlN).
 9. A magnetic write system comprising: a writemedium; and a perpendicular magnetic write head, the perpendicularmagnetic write head including: a main magnetic pole layer leadingmagnetic flux to the write medium, and the main magnetic pole layerhaving an internal stress of a specified direction; an auxiliarymagnetic pole layer disposed on a trailing side of the main magneticpole layer, the auxiliary magnetic pole layer being recessed from themain magnetic pole layer; a nonmagnetic layer disposed in a layer sameas the auxiliary magnetic pole layer and in front of the auxiliarymagnetic pole layer, the nonmagnetic layer having an internal stress ofa direction same as that of the main magnetic pole layer; and a writeshield layer disposed in a layer same as the auxiliary magnetic polelayer and in front of the auxiliary magnetic pole layer, the writeshield layer being separated from the main magnetic pole layer with agap layer in between, wherein the nonmagnetic layer is arranged to fillup a space between the auxiliary magnetic pole layer and the writeshield layer.
 10. The magnetic write system according to claim 9,wherein the write medium includes a magnetization layer and a softmagnetic layer in this order from a side close to the perpendicularmagnetic write head.
 11. A magnetic write system comprising: a writemedium; and a perpendicular magnetic write head, the perpendicularmagnetic write head including: a main magnetic pole layer leadingmagnetic flux to the write medium, and the main magnetic pole layerhaving an internal stress of a specified direction; an auxiliarymagnetic pole layer disposed on a leading side of the main magnetic polelayer, the auxiliary magnetic pole layer being recessed from the mainmagnetic pole layer; a nonmagnetic layer disposed in a layer same as theauxiliary magnetic pole layer and in front of the auxiliary magneticpole layer, the nonmagnetic layer having an internal stress of adirection same as that of the main magnetic pole layer; a write shieldlayer disposed on the trailing side of the main magnetic pole layer inan area close to an airbearing surface, the write shield layer beingseparated from the main magnetic pole layer with a gap layer in between;and another nonmagnetic layer disposed in a layer same as the writeshield layer at the back of the write shield layer, the anothernonmagnetic layer having an internal stress of a direction same as thatof the main magnetic pole layer.
 12. The magnetic write system accordingto claim 11, wherein the write medium includes a magnetization layer anda soft magnetic layer in this order from a side close to theperpendicular magnetic write head.